Bicycle chain guide with height adjustment

ABSTRACT

A chain guide for a bicycle having may include a base frame and a height adjustment member connected to the base frame and slidable relative to the base frame and lockable in a first position by engaging a first locking member. A retaining member may be pivotally connected to the height adjustment member and may be pivotable about a pivot axis a retaining position, in which the retaining member is positioned to obstruct lateral movement of the chain away from the chainring thereby preventing lateral misalignment between the chain and the chainring, and a removal position, in which the retaining member does not obstruct lateral movement of the chain away from the base frame while the height adjustment member is locked in the first position. The pivot axis may be spaced apart from the first locking member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of 35 USC 119 based on the priorityof U.S. Provisional Patent Application 62/204,764, filed Aug. 13, 2015and entitled Bicycle Chain Device with Height Adjustment, the entiretyof which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a bicycle chain guide, and inparticular, to a bicycle chain guide for use with a bicycle drivetrainhaving a chainring mounted to a front crankset.

INTRODUCTION

U.S. Pat. No. 6,533,690 discloses a bicycle includes a conventionalpedal crank and chain drive together with a conventional derailleurshifting mechanism operative to selectively transfer the drive chainbetween alternative rear sprockets of the bicycle drive system. A chainring is rotatable in response to pedal crank rotation to transfer pedalcrank power to the rear sprockets. A pair of guide blocks definerespective internal guide channels through which the drive chain passestoward and from engagement with the chain ring. The guide blocks aremaintained at their respective positions by a guide support platesecured to the bicycle frame.

U.S. Pat. No. 8,235,849 discloses a combined chain guide and chain ringprotector for a bicycle for off-road use having a lower bracket sleeve,a chain ring around which a drive chain extends and a chain ring outerradius. The protector includes a mounting bracket secured at the lowerbracket sleeve and a guard mounted thereto. An outer edge of the guardextends beyond the outer radius of the chain ring, thereby protecting aportion of the chain ring from inadvertent impacts. The chain guideextends from the mounting bracket along a path of the drive chain, andpreferably includes an upper guide having an inner barrier positionedinboard of the bicycle chain an outer barrier positioned outboard of theinner barrier and an upper barrier positioned above the bicycle chainfor preventing the chain from derailing from the chain ring in an upwarddirection.

SUMMARY

A chain guide for a bicycle can be configured so that its retainingmember can be operated (i.e. moved from a chain retaining position to achain removal position and/or detached) independently of adjusting theheight of the retaining member relative to the chainring. For example,the chain guide may include a base frame that can be connected to theframe of a bicycle, preferably adjacent the front chainring (butalternatively in other locations). The base frame can be attached to theframe using any suitable fasteners, including bolts. The retainingmember can be movably mounted on the base frame so that its height canbe varied based on a particular chainring and/or chain that is beingused by a rider. This may be helpful if the chain guide is provided asan aftermarket part that can be used with a variety of bikes and cranksets, and/or if a user changes chain rings on their bicycle. Once theretaining member has been positioned at a desired height relative to agiven chain ring, it may be advantageous in some instances to allow theretaining member to be operated without having to re-set and/orre-adjust its height setting. For example, a rider may wish to move theretaining member into a removal position which can allow the chain to beremoved, for example for cleaning or inspection, and then return theretaining member to a retaining position, in which it acts to preventdisengagement of the chain from the chain ring.

Optionally, to help facilitate independent height positioning andoperation of the retaining member, the chain guide may include a heightadjustment member that extends between the base frame and the retainingmember. The height adjustment member may be movable relative to theframe to adjust the height of the retaining member, and may be locked ina desired position using a first locking member. The first lockingmember may optionally include the fastener that is used to attach theheight adjustment member to the base frame, or may include a separatelocking device. Then the first locking member is engaged, the heightadjustment member may be fixed relative to the base frame. The retainingmember may be movably coupled to the height adjust member, and may bemovable between its retaining and removal positions while the heightadjustment member remains locked in place (i.e. while the first lockingmember is engaged). Because the first locking member need not bedisengaged to allow operation of the retaining member, the heightposition of the retaining member may set.

Preferably, the retaining member is pivotable relative to the heightadjustment member to move between its retaining and removal positions,and is pivotable about a pivot axis that is spaced apart from the firstlocking member. This may allow the retaining member to be pivotedwithout unlocking the height adjustment member. This may also allow thefirst locking member to be positioned in a relatively inaccessible,inconvenient location (as it is accessed less frequently) while thepivot axis is located in a desired location, for example proximate theperiphery of the chainring and accessible to the user.

Optionally, the retaining member may be connected to the heightadjustment member using a pivotable mounting fastener, whereby themounting fastener is co-axial with the pivot axis, and is spaced apartfrom the first locking member. Preferably, the fastener used to mountthe retaining member to the height adjustment member is separate fromthe fastener used to mount the height adjustment member to the baseframe. This may help facilitate independent operation/movement of thecomponents, and may allow the retaining member to be detached (forexample by removing its fastener) without requiring the detachment ofthe height adjustment member or the loosening of its fastener (i.e.without disturbing the height setting).

Optionally, the retaining member may be lockable in the retainingposition, the removal position, or both using a second locking member.The second locking member may include the mounting fastener that is usedto attach the retaining member to the height adjustment member. Forexample, the fastener may be a threaded type fastener that can betightened to prevent movement of the retaining member relative to theheight adjustment member, and loosened to allow relative movement.Alternatively, the second locking member may be separate from themounting fastener. This may allow the second locking member to havevarious configurations and may allow the locking member to be positionedat a different location than the pivot joint. For example, the secondlocking member may include a pin that engages the retaining member at alocation that is spaced from the mounting fastener, or the co-operationbetween a detent and a complimentary receiving portion provided on theretaining member and height adjustment member. Optionally, the secondlocking member may be engageable and disengagable by hand, i.e. withoutthe need for tools to loosen a threaded fastener or the like, which mayallow a user to more easily manipulate the retaining member while on thetrail or otherwise without tools.

One embodiment of a bicycle chain guide may have a height adjustmentmechanism that is independent of the mounting mechanisms for both itschain retaining member and bicycle frame mounting portion.

One embodiment of a bicycle chain guide may have a chain retainingmember mounted such that it can be removed or rotated without affectingthe chain retaining member height once reinstalled.

One embodiment of a bicycle chain guide for use with a bicycledrivetrain having one chainring on the front crankset may have a chainretaining member mounted such that it can be removed or rotated to allowinstallation, removal or performance of maintenance to the chain,chainring or crankset without having to reset the height of the chainretaining member of the chain device.

In accordance with one broad aspect of the teachings described herein, achain guide for a bicycle having a chainring and a chain can include abase frame having a mounting portion for connecting to a bicycle. Aheight adjustment member may be connected to the base frame and may beslidable relative to the base frame so that the height adjustment memberis movable relative to the base frame and can be selectably locked in afirst position by engaging a first locking member. A retaining membermay be pivotally connected to the height adjustment member and may bepivotable about a pivot axis while the height adjustment member islocked in the first position. The pivot axis may be spaced apart fromthe first locking member. When the base frame is connected to thebicycle with the height adjustment member locked in the first positionand the retaining member positioned proximate a periphery of thechainring the retaining member may be pivotable between a retainingposition, in which the retaining member is positioned to obstructlateral movement of the chain away from the chainring thereby preventinglateral misalignment between the chain and the chainring, and a removalposition, in which the retaining member does not obstruct lateralmovement of the chain away from the base frame.

The retaining member may have a first end and a second end thatcomprises the pivot axis and is spaced from the first end in a directionthat is parallel a direction of travel of the chain relative to theretaining member.

The retaining member may include a bottom face that is downward facingwhen the base frame is connected to the bicycle and the retaining memberis in the retaining position, and an end face at the second end. Adistance between the pivot axis and the bottom face in a first directionmay be greater than a distance between the pivot axis and the end facein a second direction that is orthogonal to the first direction.

The retaining member may be selectably locked in the retaining positionby engaging and disengaging a second locking member that is spaced apartfrom the first locking member. The second locking member may include afastener that extends through the retaining member, and may be engagedand disengaged independent of whether the first locking member isengaged or disengaged.

The fastener may be co-axial with the pivot axis whereby the retainingmember pivots about second locking member.

When the base frame is connected to the bicycle, the height adjustmentmember is in the first position and the retaining member is positionedproximate the periphery of the chainring, the retaining member may belaterally translated away from the base frame in the direction of thepivot axis while in the removal position and may be obstructed fromtranslating away from the base frame by the chainring when in theretaining position.

When the base frame is connected to the bicycle with the heightadjustment member locked in the first position and the retaining memberis positioned proximate a periphery of the chainring and in the removalposition the retaining member is translatable laterally away from theheight adjustment member while the height adjustment member is locked inthe first position to detach the retaining member from the heightadjustment member.

The retaining member may include a first chain retaining face and anopposing second chain retaining face that is laterally spaced apart fromand faces the first retaining surface, whereby when the base frame isconnected to the bicycle the chain is disposed laterally between thefirst and second chain retaining faces, and wherein the retaining memberpivots in a first direction about the pivot axis from the retainingposition to the removal position substantially the entire first andsecond chain retaining surfaces move in the first direction away fromthe chain.

The retaining member may include a first chain retaining face and anopposing second chain retaining face that is laterally spaced apart fromand faces the first chain retaining surface, whereby when the base frameis connected to the bicycle and the retaining member is in the retainingposition the chain is disposed laterally between the first and secondchain retaining faces and a clearance plane defining an upper surface ofthe chain intersects the first and second chain retaining faces, andwhen the retaining member is in the removal position it is disposedentirely above the clearance plane.

The height adjustment member may include a sliding surface and the baseframe includes a complimentary abutment surface such that engagementbetween the sliding surface and abutment surface prevents rotation ofthe height adjustment member relative to the base frame while permittingonly linear translation therebetween.

The base frame may be securable to the bicycle using at least one basefastener that is spaced apart from the first locking member. The firstlocking member may be engaged and disengaged independent of the at leastone base fastener.

When the base frame is connected to the bicycle the retaining member mayform the upper most part of the chain guide when the height adjustmentmember is in the first position and when the height adjustment member ismoved to a different, second position relative to the base frame.

In accordance with another aspect of the teachings described herein, achain guide for a bicycle having a chainring and a chain may include abase frame having a mounting portion for connecting to a bicycle. Aheight adjustment member may be connected to the base frame and may beslidable relative to the base frame whereby the height adjustment memberis movable relative to the base frame and can be selectably locked in afirst position by engaging a first locking member. A retaining membermay be pivotally mounted to the height adjustment member by a mountingfastener that defines a pivot axis and extends through the retainingmember. The mounting fastener may be being spaced apart from the firstlocking member. The retaining member may be pivotable about the pivotaxis while the first locking member is engaged between a retainingposition, in which the retaining member is positioned to obstructlateral movement of the chain away from the chainring when the baseframe is connected to the bicycle thereby preventing lateralmisalignment between the chain and the chain ring, and a removalposition, in which the retaining member does not obstruct lateralmovement of the chain away from the base frame.

The first locking member may include a first fastener securing theheight adjustment member to the base frame, wherein the first lockingmember is disengaged by loosening the first fastener and engaged bytightening the first fastener. A second locking member may be spacedapart from the first locking member and may be used for locking theretaining member to the height adjustment member such that the retainingmember is movable relative to the height adjustment member when thesecond locking member is disengaged and is not movable relative to theheight adjustment member when the second locking member is engaged. Thesecond locking member may disengagable independently of the firstlocking member.

The second locking member may include the mounting fastener, and may bedisengaged by loosening the mounting fastener and be engaged bytightening the mounting fastener.

The second locking member may be spaced apart from the mountingfastener.

The second locking member may include a detent provided on one of theretaining member and the height adjustment member that engages with acomplimentary receiving portion on the other one of the retaining memberand the height adjustment member. The second locking member may bedisengaged by disengaging the detent from the receiving portion.

In accordance with another broad aspect of the teachings describedherein, a chain guide for a bicycle having a chainring and a chain mayinclude a base frame having a mounting portion for connecting to abicycle. A height adjustment member may be connected to the base frameand may be slidable relative to the base frame whereby the heightadjustment member is movable relative to the base frame and can beselectably locked in a first position by engaging a first lockingmember. A retaining member may be pivotally mounted to the heightadjustment member by a mounting fastener that defines a pivot axis andextends through the retaining member to engage the height adjustmentmember. When the base frame is connected to the bicycle with the heightadjustment member locked in the first position and the retaining memberis positioned proximate a periphery of the chainring the retainingmember may be pivotable about the pivot axis between a retainingposition, in which the retaining member is positioned to obstructlateral movement of the chain away from the chainring when the baseframe is connected to the bicycle thereby preventing lateralmisalignment between the chain and the chain ring, and a removalposition, in which the retaining member does not obstruct lateralmovement of the chain away from the base frame. Also, while theretaining member is in the removal position the mounting fastener may beremovable whereby the retaining member may be translatable laterallyaway from the height adjustment member to detach the retaining memberfrom the height adjustment member.

The retaining member may be lockable in the retaining position byengaging a second locking member that is spaced apart from and operableindependently from the first locking member.

The second locking member may include the mounting fastener, and thesecond locking member is disengaged by loosening the mounting fastenerand engaged by tightening the mounting fastener.

In accordance with another broad aspect of the teachings describedherein, a chain guide for a bicycle having a chainring and a chain mayinclude a base frame having a mounting portion for connecting to abicycle. A height adjustment member may be connected to the base frameand may be slidable relative to the base frame whereby the heightadjustment member is movable relative to the base frame and is lockablein a first position by engaging a first locking member. A retainingmember may be pivotally connected to the height adjustment member andmay be pivotable about a pivot axis that is spaced apart from the firstlocking member while the height adjustment member is locked in the firstposition. The retaining member may be lockable in a retaining positionby engaging a second locking member that extends through at least aportion of the retaining member. The second locking member may be spacedapart from the first locking member and can be engaged and disengagedindependent of whether the first locking member is engaged ordisengaged. When the base frame is connected to the bicycle with theheight adjustment member locked in the first position and the retainingmember positioned proximate a periphery of the chainring the retainingmember is pivotable between the retaining position, in which theretaining member is positioned to obstruct lateral movement of the chainaway from the chainring thereby preventing lateral misalignment betweenthe chain and the chainring, and a removal position, in which theretaining member does not obstruct lateral movement of the chain awayfrom the base frame.

The retaining member may have a first end and a second end thatcomprises the pivot axis and is spaced from the first end in a directionthat is parallel a direction of travel of the chain relative to theretaining member.

The first end may be spaced apart from the height adjustment member andthe second end may be adjacent and overlie the height adjustment member.

The retaining member may include a bottom face that is downward facingwhen the base frame is connected to the bicycle and the retaining memberis in the retaining position, and an end face at the second end. Adistance between the pivot axis and the bottom face in a first directionmay be greater than a distance between the pivot axis and the end facein a second direction that is orthogonal to the first direction.

The retaining member may be connected to the height adjustment member bya mounting fastener that extends through the retaining member and isco-axial with the pivot axis whereby the retaining member pivots aboutthe mounting fastener.

The second locking member may include the mounting fastener and may bedisengaged by loosening the mounting fastener and engaged by tighteningthe mounting fastener and the retaining member pivots about secondlocking member.

The second locking member may include a threaded fastener and the secondlocking member may be disengaged by loosening the threaded fastener andengaged by tightening the threaded fastener.

The threaded fastener may extend through the retaining member andthreadingly engage the height adjustment member.

The first locking member may include a first threaded fastener and isdisengaged by loosening the first threaded fastener and engaged bytightening the first threaded fastener. The second locking member mayinclude a second threaded fastener that is parallel to and offset fromthe first threaded fastener. The second locking member may be disengagedby loosening the second threaded fastener and engaged by tightening thesecond threaded fastener.

When the base frame is connected to the bicycle, the height adjustmentmember is in the first position and the retaining member is positionedproximate the periphery of the chainring, the retaining member may belaterally translated away from the base frame in the direction of thepivot axis while in the removal position and may be obstructed fromtranslating away from the base frame by the chainring when in theretaining position.

When the base frame is connected to the bicycle with the heightadjustment member locked in the first position and the retaining memberis positioned proximate a periphery of the chainring and in the removalposition the retaining member may be translatable laterally away fromthe height adjustment member while the height adjustment member islocked in the first position to detach the retaining member from theheight adjustment member.

The retaining member may include a first chain retaining face and anopposing second chain retaining face that is laterally spaced apart fromand faces the first chain retaining surface. When base frame isconnected to the bicycle the chain may be disposed laterally between thefirst and second chain retaining faces. When retaining member pivots ina first direction about the pivot axis from the retaining position tothe removal position substantially the entire first and second chainretaining surfaces move in the first direction away from the chain.

The retaining member may include a first chain retaining face and anopposing second chain retaining face that is laterally spaced apart fromand faces the first retaining surface. When the base frame is connectedto the bicycle and the retaining member is in the retaining position thechain is disposed laterally between the first and second chain retainingfaces and a clearance plane defining an upper surface of the chain mayintersect the first and second chain retaining faces. When the retainingmember is in the removal position it may be disposed entirely above theclearance plane.

The height adjustment member may include a sliding surface and the baseframe may include a complimentary abutment surface such that engagementbetween the sliding surface and abutment surface prevents rotation ofthe height adjustment member relative to the base frame while permittingonly linear translation therebetween.

The base frame may be securable to the bicycle using at least one basefastener that is spaced apart from the first locking member, and whereinthe first locking member can be engaged and disengaged independent ofthe at least one base fastener.

When the base frame is connected to the bicycle the retaining member mayform the upper most part of the chain guide when the height adjustmentmember is in the first position and when the height adjustment member ismoved to a different, second position relative to the base frame.

In accordance with another broad aspect of the teachings describedherein, a chain guide for a bicycle having a chainring and a chain mayinclude a base frame having a mounting portion for connecting to abicycle. A height adjustment member may be connected to the base frameand slidable relative to the base frame whereby the height adjustmentmember is movable relative to the base frame and is lockable in a firstposition by engaging a first locking member. A retaining member may bepivotally connected to the height adjustment member and may be spacedapart from the first locking member. The retaining member may bepivotable about a pivot axis while the height adjustment member islocked in the first position and ay include a first chain retaining faceand an opposing second chain retaining face that is laterally spacedapart from and faces the first retaining surface a first chain retainingface. When the base frame is connected to the bicycle with the heightadjustment member locked in the first position and the retaining memberpositioned proximate a periphery of the chainring the retaining membermay be pivotable between a retaining position, in which the chain isdisposed laterally between the first and second chain retaining faceswhereby engagement between the chain and the first and second chainretaining faces obstructs lateral movement of the chain away from thechainring, and a removal position, in which the first and second chainretaining faces are spaced above the chain and the retaining member doesnot obstruct lateral movement of the chain away from the base frame. Theretaining member may be lockable in the retaining position by engaging asecond locking member that extends through at least a portion of theretaining member, and wherein the second locking member is spaced apartfrom the first locking member and can be engaged and disengagedindependent of whether the first locking member is engaged ordisengaged.

The retaining member may be connected to the height adjustment ember bya mounting fastener that extends through the retaining member andengages the height adjustment member and is co-axial with the pivot axiswhereby the retaining member pivots about the mounting fastener, andwherein the mounting fastener is spaced apart from the first and secondchain retaining faces.

The first locking member may include a first threaded fastener whichextends through a slot in the base frame and is disengaged by looseningthe first threaded fastener and engaged by tightening the first threadedfastener, and the second locking member may include a second threadedfastener that is parallel to and offset from the first threadedfastener. The second locking member may be disengaged by loosening thesecond threaded fastener and engaged by tightening the second threadedfastener.

When the retaining member is in the retaining position a clearance planedefined by an upper surface of the chain may intersect the first andsecond chain retaining faces. The retaining member may be pivotablewithout disengaging the first locking member into the removal positionin which the entirety of the retaining member is disposed entirely abovethe clearance plane.

Other aspects and features will become apparent, to those ordinarilyskilled in the art, upon review of the following description of someexemplary embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings included herewith are for illustrating various examples ofarticles, methods, and apparatuses of the present specification. In thedrawings:

FIG. 1 is a side plan view of a bicycle drivetrain;

FIG. 2 is a side plane view of one example of a chain guide, with aheight adjustment member in a first position and a retaining member in aretaining position;

FIG. 3 is a side plane view of the chain guide of FIG. 2, with a heightadjustment member in a second position and a retaining member in theretaining position;

FIG. 4 is a side plane view of the chain guide of FIG. 2, with a heightadjustment member in a third position and a retaining member in theretaining position;

FIG. 5 is a side plane view of the chain guide of FIG. 2, with a heightadjustment member in the second position and the retaining member in aremoval position;

FIG. 6 an exploded perspective view of the chain guide of FIG. 2,illustrated adjacent a portion of a bicycle frame;

FIG. 7 is side plan view of the chain guide of FIG. 4 in use with thebicycle drive train of FIG. 1;

FIG. 8 is a top view of the chain guide of FIG. 4 positioned adjacent achainring and chain;

FIG. 9 is a side plan view of the arrangement of FIG. 10, with theretaining member in a retaining position; and

FIG. 10 is the side plan view of FIG. 11, with the retaining member in aremoval position.

DETAILED DESCRIPTION

Various apparatuses or processes will be described below to provide anexample of an embodiment of each claimed invention. No embodimentdescribed below limits any claimed invention and any claimed inventionmay cover processes or apparatuses that differ from those describedbelow. The claimed inventions are not limited to apparatuses orprocesses having all of the features of any one apparatus or processdescribed below or to features common to multiple or all of theapparatuses described below. It is possible that an apparatus or processdescribed below is not an embodiment of any claimed invention. Anyinvention disclosed in an apparatus or process described below that isnot claimed in this document may be the subject matter of anotherprotective instrument, for example, a continuing patent application, andthe applicants, inventors or owners do not intend to abandon, disclaimor dedicate to the public any such invention by its disclosure in thisdocument.

A conventional bicycle drivetrain 10 may include a front crankset 20 anda multi-gear rear cassette 30, a rear derailleur 50 and a chain 40 thatconnects the front crankset 10 and the multi-gear rear cassette 30. Themulti-gear rear cassette 30 is, in this example, comprised of multiplechainrings of different diameters which offer a bicyclist a multitude ofspeed options. The multi-gear rear cassette 30 can be rotatablyconnected to a rear wheel of the bicycle (not shown). The front crankset20 is connected to the bicycle frame (not shown in FIG. 1) and comprisesa rotatably attached chainring 22. The bicyclist rotates the crankset bypedaling which moves the chain around the multi-gear rear cassette,propelling the bicycle.

Bicycle drivetrains may include multiple chainrings 22 mounted to thefront crankset to provide the rider with more speed options. However,some bicycles have only one chainring 22 at the front crankset 20, asillustrated in FIG. 1. The single chainring 22 for a bicycle drivetrainwith only one chainring mounted to the front crankset may be anysuitable chainring, and may have a diameter from tooth counts of 26T to38T depending on the strength of the rider and the terrain the bicyclewill be operated on.

When a bicycle is ridden quickly over rough terrain, the length of chain40 suspended between the top of the front chaining 22 and the top of therear cassette 30, can become very active, moving up-and-down and movingside-to-side. This chain motion can cause the chain to derail the frontchainring 22. For example, the chain may derail if the crankset isrotated or pedaled forwardly at a time when the chain 40 is notlaterally aligned with the chainring 22, for example if the chain 40 isdisplaced upwardly or downwardly as illustrated in FIG. 10.

Chain guides have been developed to keep the chain engaged with thefront chainring over rough terrain. Known chain guides can connect tothe bicycle frame and may include a retaining member which may bepositioned proximate the periphery of the front chainring 22. Due to thevarying size of chainrings 22 in different bicycles and the desire toperiodically reposition the retaining member for maintenance, it isdesirable to make the retaining member of the chain guidemovable/re-positionable.

As such, conventional chain guides have included a chain retainingmember that can be raised and lowered (i.e. moved farther from and/orcloser to the periphery of the chainring). Often a mechanism thatprovides for the height adjustment of the retaining member is slot orthe like formed in the mounting plate to which the retaining member isattached. This may produce a chain guide that is bulky above the chainretaining member in some instances. For example, when the chainretaining member is adjusted to accommodate a chainring smaller than itshighest capacity, there can be a portion of the base frame that extendsabove the chain retaining member. This portion of base frame thatextends above the chain retaining member can interfere with the bicycleframe causing frame damage or incompatibility.

Generally, the chain retaining member chain guides also tend to inhibitaccess to the chain, front chainring and crankset. In some known chainguides the same mechanism controls both connection of the retainingmember to the rest of the chain guide and the height adjustment of theretaining member. In such arrangements, installing, removing or performmaintenance on the chain, chainring or crankset typically also resultsin having to reset the height of the chain retaining member. As aresult, conventional chain guides typically require that a heightadjustment bolt be loosened to adjust the height of the retaining memberin order to perform routine maintenance on the drivetrain.

In some known chain guides, the retaining member can be operatedsomewhat independently of its height adjustment. However, in some suchdesigns, such as GRID ISCG Chainguide manufactured by Gravity Componentsof Mukileto, Wash., a single fastener is used to attach the retainingmember to the rest of the chain guide, as well as lock the retainingmember in at a given height. In such configurations, removing theretaining member requires removing the fastener, which also unlocks theheight adjustment. When the retaining member is re-attached and thefastener re-installed, the retaining member height needs to be re-set.This configuration also requires that the locking member for controllingthe height passes through the retaining member, and the rest of thechain guide, such as the mounting plates and the like, must extend tothe upper most position that the retaining member is movable to, meaningthat portions of the bracket are likely to be exposed when the retainingmember is in a position other than its uppermost.

In other such designs, such as a BB Chainguide manufactured by PaulComponent Engineering of Chico, Calif., a retaining member may be movedor detached from the rest of the chain guide while the height adjustmentremains locked, but only when the chain guide is separated from thebicycle. In this configuration, the configuration of the chain guide issuch that when it is mounted to the bicycle in a use position—i.e. whenthe retaining member is positioned sufficiently proximate the peripheryof the chainring to inhibit chain derailment—the presence of the chainand chainring limit the movement of the retaining member without alsoadjusting its height. For example, in this design the retaining membercannot be moved into a chain removal position while at its use heightbecause rotating the retaining member causes interference betweenportions of the retaining member and the chain. To allow the desiredrotation, the retaining member can first be raised, to be clear of thechain, and then rotated. At that point, rotating the retaining membermay be somewhat redundant, as merely raising the retaining member may beadequate to provide the desired access to the chain. Similarly,interference between the retaining member and the chain or chainring inthis design prevents the retaining member from being laterally movedaway from the rest of the chain guide, which inhibits removing theretaining member. The retaining member may be removed when spacedfarther from the chainring by altering the height or when detached fromthe bicycle, but this does not allow a user to easily remove andre-attached the retaining member while the chain guide is in use (i.e.while mounted to the bicycle and possibly in a remote location) withoutalso adjusting the height.

Accordingly, there may be a need for a chain guide in which theretaining member may be operated and/or removed, preferably while thechain guide is mounted to the bicycle, without modifying the height ofthe retaining member. The may be a need for a chain guide where a usercan install, remove and/or move the retaining member or performmaintenance to the chain, chainring or crankset without having torelease the height locking mechanism or otherwise adjust the height ofthe chain retaining member.

Accordingly, there may be a need for a chain guide that can be adjustedfor a full range of front chainring sizes while eliminating the mountingplate portions that would typically extend above the chain retainingmember in known designs.

There may also be a need for a chain guide in which the fastener and/orlocking mechanism for setting the height of the retaining member neednot extend through or otherwise engage the retaining member. This mayallow the fastener and/or locking mechanism for setting the height to beplaced in a less desirable and/or less accessible area (as it isgenerally accessed less frequently) that is spaced apart from where theretaining member is connected to the rest of the chain guide.

Referring to FIGS. 2-5, on example of a chain guide 100 that is usablewith the bicycle drive train 10 includes a base frame 102, a heightadjustment member 104 and a retaining member 106. The height adjustmentmember 104 is movable relative to the base frame 102 to adjust theheight of the retaining member 106 relative to the chainring, such aschainring 22. Preferably, the height adjustment member 104 can be lockedin a plurality of different positions relative to the base frame 102,using a suitable locking mechanism. The retaining member 106 is mountedto and is movable relative to the height adjustment member 104.Preferably, the retaining member 106 is movable between a retainingposition and a removal position while the chain guide 100 is mounted toa bicycle.

When in the retaining position (see for example FIGS. 2 7 and 9), theretaining member 106 is positioned proximate the periphery of thechainring 22 and physically obstructs the lateral and/or verticaldisengagement of the chain 40 from the chainring 22, while allowing thedesired motion of the chain 40 around the chainring 22.

When in the removal position (see for example FIGS. 5 and 10) theretaining member 106 is moved relative to the height adjustment member104 (for example pivoted, translated, detached and the like) to aposition in which the retaining member 106 does not physically obstructor otherwise interfere with removal of the chain 40 from the chainring22 and/or in which a user may access the chain 40 and chainring 22 forinspection or maintenance. In the illustrated embodiment, while thechain guide is mounted to the bicycle the retaining member 106 can bemoved relative to the height adjustment member 104, and can be detachedfrom the height adjustment member 104, without moving the heightadjustment member 104 relative to the base frame 102 and withoutdisengaging the locking mechanism that secures the height adjustmentmember 104 to the base frame 102.

In the illustrated embodiment, the base frame 102 includes a mountingportion 112 that is configured to connect to a bicycle. The mountingportion may have a variety of different configurations to accommodatedifferent bicycles and different industry mounting patterns, and inillustrated embodiment includes two apertures 110 that are spaced apartfrom each other and are configured to receive suitable base mountingfasteners, such as mounting bolts 111 which can be threaded into bosses113 on the bicycle frame 115 (FIG. 6). In this example the apertures 110are elongate slots, which may help facilitate mounting of the base frame102 on a variety of bicycles and/or may allow for some fine-tuning ofthe base frame 102 position on a given bicycle. Alternatively, theapertures 110 may be round holes or any other suitable configuration.

The base frame 102 also includes an upper portion 114 that is spacedapart from the mounting portion 112 and is positioned so that when thebase frame is mounted to the bicycle the upper portion 114 will be at ahigher elevation than the mounting portion 112. In this example, theupper portion 114 is configured to be connected to and support theheight adjustment member 104. The upper portion 114 may have anysuitable configuration that allows for the desired connecting andre-positioning of the height adjustment member 104 relative to the baseframe 102, and may include any desirable connecting portion. Theconnection portion may be configured to allow the height adjustmentmember 104 to be movably connected to the base frame 102, and may beconfigured to facilitate sliding, rotating, detachment and re-attachmentat a variety of spaced attachment points and the like.

Referring to FIGS. 2, 3 and 6, in the illustrated example, the upperportion 114 includes a track 116 that is configured to slidably receivea mounting fastener 118 that fastens the height adjustment member 104 tothe base frame 102. The opening may be of any suitable shape, anddefines a movement path along with the height adjustment member 104travels. In this example, the track portion is a generally linear,elongate slot 116 that extends along a linear slot axis 120. The trackportion 116 in this example is a through hole that extends completelythrough the base frame 102 in a lateral direction, but in otherembodiments may be a closed bottom slot, channel, groove or the like.While shown as a linear slot, in some embodiments the slot 116 may benon-linear, and may be curved or otherwise configured.

In the illustrated example, the fastener 118 extends from the outer side124 of the base frame 102, (i.e. the side that is outwardly facing whenthe base frame 102 is mounted to the bicycle) through the open slot 116and threadingly engages a corresponding opening 122 (FIG. 6) on theheight adjustment member 104 which is positioned on the opposing innerside 126 of the base frame 102.

Preferably, the chain guide 100 can include a locking member for lockingthe height adjustment member 104 in a fixed position relative to thebase frame 102. In this example, the fastener 118 functions as both anattachment mechanism and a locking mechanism that can be selectablyengaged and disengaged by a user. For example, tightening the fastener118 will increase the friction between the base frame 102 and the heightadjustment member 104 thereby locking the height adjustment member 104in a given position. To unlock the height adjustment member 104, thelocking mechanism can be disengaged by loosening fastener 118, butoptionally not completely removing, the fastener 118. With the fastener118 loosened but still extending through the slot 116, the heightadjustment member can be moved along the length of the slot 116, andre-locked at any location therealong.

Alternatively, a separate locking member may be provided to lock theheight adjustment member 104 in place. For example, a separate pin orthe like may be insertable into corresponding apertures to fix theposition of the height adjustment member 104, or a clamping mechanismmay be used to grasp and hold the height adjustment member 104.

In the illustrated embodiment, the fastener 118 is separate from andspaced apart from the mounting bolts 111. In this configuration, thefastener 118 can be tightened and loosened without affecting themounting bolts 111, and vice versa. This may allow the chain guide 100to be attached to and removed from a bicycle without unlocking thefastener 118 or otherwise altering the height setting. This may alsoallow the height adjustment member 104 locking member (i.e. fastener 118in this example) to be disengaged without affecting the connectionbetween the base frame 102 and the bicycle.

In some embodiments, the height adjustment member 104 may be movable intwo or more degrees of freedom relative to the base frame 102. Forexample the height adjustment member 104 may be translatable along thelinear slot 116 and also rotatable, for example about the axis of thefastener 118. Alternatively, movement of the height adjustment member104 may be constrained so that it is only movable in one degree offreedom, i.e. so that it is only translatable relative to the base frame102. This may help ensure that the retaining member 106, which ismovable with the height adjustment member 104, is only moved closer andfarther from the periphery of the chainring 20, and isn't moved intounwanted positions. Optionally, the chain guide may include any suitableanti-rotation mechanism to help constrain the movement of the heightadjustment member 104 in a desired manner.

In the illustrated example, the chain guide includes an anti-rotationmechanism that includes a sliding surface 128 on the height adjustmentmember 104 that is configured to slide against a complimentary abutmentsurface 130 (FIG. 4) on the base frame 102. The surfaces 128 and 130 areboth generally planar and are slidable relative to each other, butengagement between the surfaces 128 and 130 restricts rotation of theheight adjustment member 104 relative to the base frame 102.

Optionally, the chain guide 100 may include one or more indicia to helpa user position the height adjustment member 104 in a desired positionrelative to the base frame 102. For example, either the base frame 102or height adjustment member 104 may include markings identifyingsuitable positions for the height adjustment member 104 when the chainguide 100 is used in combination with different sized chainrings 22. Inthe illustrated example, the height adjustment member 104 includesindicia in the form of numbers 132 provided on the outer face of theheight adjustment member 104. When the height adjustment member 104 istranslated upwardly relative to the base frame 102 more numbers 132 maybe revealed, and when the height adjustment member 104 is moveddownwardly the numbers 132 are obscured. In this example, the numbers132 relate to the number of teeth on the chainring 22, and user can movethe height adjustment member 104 until the number 132 that correspondsto the number of teeth on his particular chainring 22 is the lowermostexposed number 132, and then tighten the fastener 118 to lock the heightadjustment member 104 in place. Alternatively, other indicia may beused.

The retaining member used with the chain guide 100 may have any suitableconfiguration. Referring to FIGS. 6 and 8, in the illustratedembodiment, the retaining member 106 includes a pair of laterally spacedapart inwardly facing chain retaining faces 134 and 136. In thisexample, the chain retaining face 134 is laterally spaced apart from thechain retaining face 136 by a lateral spacing 138 (FIG. 8) that isgreater than the lateral thickness 140 of the chain 40. In thisconfiguration, when the chain guide 100 is mounted to the bicycle andthe retaining member is in the use position, as shown in FIG. 7 and insimplified FIGS. 8 and 9, the chain retaining faces 134 and 136 arepositioned on opposite sides of the chain 40 and are laterally spacedapart from the side faces 41 and 42 of the chain 40 but are close enoughto limit lateral movement of the chain 40. That is, if the chain 40 isdeflected laterally its side faces 42 and 41 will come into contact withone of the chain retaining faces 134 and 136 before it has becomesufficiently misaligned from the chainring 22 to cause a derailment.Contact with the chain retaining faces 134 and 136 will urge the chain40 back to its laterally aligned position. This may help limitside-to-side misalignment of the chain 40.

When the chain guide 100 is in use, the retaining member 106 can beplaced in its retaining position where it is in close proximity to theperiphery of the chainring 22 and where the chain is laterally betweenthe chain retaining faces 134 and 136. To provide access to the chainand/or to facilitate its removal from the chainring 22, the retainingmember can be moved to its removable position in which at least one of,and optionally both of, the chain retaining faces 134 and 136 are movedaway from the chain 40.

In the illustrated embodiment, the retaining member 106 is coupled tothe upper end of the height adjustment portion using a mounting fastener142 that extends through a corresponding aperture 144 in the retainingmember 106 and threadingly engages a corresponding bore 146 in the upperend of the height adjustment member 104. In this arrangement, themounting fastener 142 attaches the retaining member 106 to the heightadjustment member 104 and also functions as a pivot joint, defining apivot axis 148, about which the retaining member 106 can pivot. That is,the retaining member 106 can pivot about the mounting fastener 142, andits axis 148, between the retaining position of FIG. 9 and the removalposition of FIG. 10.

The mounting fastener 142 may be oriented at any desirable angle and/ororientation, and in the illustrated embodiment is oriented so that thepivot axis 148 is generally parallel to the axis of rotation of thechainring 22, and is generally orthogonal to the linear slot axis 120.Because the mounting fastener 142 is separate from, and spaced apartfrom the fastener 118, it can be positioned in a location where thepivot axis 148 is offset from the slot axis 120 by an offset distance150 (FIG. 2). This may help facilitate positioning the pivot axis 148and fastener 142 in a desired location, without being constrained by thelocation or configuration of the slot 116 or fastener 118.

Optionally, when the head of the fastener 142 (i.e. the portion engagedby the tool of a user) is at least partially received within theretaining member 106 and remains exposed when the chain guide 100 isfully assembled. Preferably, the head of the fastener 142 is exposed onthe same side of the chain guide as the head of the fastener 118, whichmay allow a user to access and manipulate both fasteners from the sameside of the chain guide 100, and optionally while the chain guide 100remains mounted to the bicycle.

Referring also to FIG. 2, in this example the pivot axis 148, andfastener 142, are also offset from the fastener 118 by height offset 152(measured in the direction of the linear slot axis 120) and from abottom surface 154 of the retaining member by a distance 156 that issubstantially the full height of the retaining member 106 in thedirection of the slot axis 120.

In the illustrated example, the chain guide 100 is configured so theretaining member 106 is connected to the height adjustment member 104 ata location that is spaced apart from, and position above location atwhich it is attached to base frame 102, via fastener 118. In thisarrangement, the fastener 142, and pivot axis 148, is positioned abovean upper end face 158 of the base frame 102 (i.e. the upper most portionof the base frame 102) when the height adjustment member 104 is in itshighest position (FIG. 4), its lowest position (FIG. 2) and allpositions in between. In this embodiment, retaining member 106 isgenerally flush with, or extends slightly beyond the upper end of theheight adjustment member 104, and is positioned so that the retainingmember 106 is the upper most portion of the chain guide 100, regardlessof the position of the height adjustment member 104. That is, no portionof the slot 116 or other portions of the base frame 102 extend beyondthe upper end of the retaining member 106 regardless of the position ofthe height adjustment member 104. This can reduce the likelihood ofportions of the base frame 102 being exposed when the height adjustmentmember 104 is in a lowered position.

Optionally, to help facilitate the desired rotation of the retainingmember 106 and chain retaining face 136 while the retaining member 106is closely spaced to the periphery of the chainring 22, the retainingmember 106 can be configured so that it can pivot about the pivot axis148 without portions of the retaining member 106 impacting or otherwisebeing obstructed by the chain or chainring. Referring to FIGS. 9 and 10,while the chain guide 100 is in use, the chain retaining faces 134 and136 are intersected by a clearance plane 160 that represents the uppersurface of the chain 40 and/or upper most extend of the teeth on thechainring 22. In this embodiment, the retaining member 106 has a firstend 162 and a second end 164 that is spaced apart from the first end 162in the direction of the chain 40. To help facilitate rotation of theretaining member 106, the fastener 142 and pivot axis 148 are disposedtoward one end of the retaining member 106, the second end 164 in theillustrated example. Referring also to FIG. 2, in this position, thedistance 156 between the pivot axis 148 and the bottom surface 154 isgreater than the distance 166 between the pivot axis 148 and an end faceat the second end 164 of the retaining member 106.

With the pivot axis 148 in this position, substantially all of theretaining member 106, and a majority of the chain retaining face 136, isdisposed on one side of the pivot axis 148 (to the left as illustratedin FIG. 9) very little of the retaining member 106 overhangs to theother side of the pivot axis 148. When the retaining member 106 ispivoted about the axis 148 so that the chain retaining face 136 movesgenerally upwardly, away from the chain (i.e. clockwise as illustratedin FIG. 9) all of the retaining member 106 is positioned above theclearance plane 160. In contrast, if the pivot axis were located towardthe middle of the retaining member (i.e. spaced between the first andsecond ends), pivoting the retaining member may cause portions on oneside of the pivot axis to move upwardly away from the clearance plane,while causing portions on the other side of the pivot axis to movedownwardly, into the clearance plane where they may interfere withaccess to or removal of the chain.

In the illustrated example, the retaining member 106 is of integrallyformed, one piece construction and the chain retaining faces 134 and 136move in unison with each other relative to the height adjustment member104 and the rest of the chain guide. This may help simplify constructionof the retaining member and/or may help reduce the number of componentsin the chain guide.

Alternatively, the chain retaining face 134 may be provided by theheight adjustment member 104 or other portion of the chain guide 100,and need not be moveable in unison with the chain retaining face 136provided on the movable retaining member 106. Optionally, if moving thechain retaining face 136 is sufficient to allow access to the chainand/or removal of the chain from the chainring, the chain retaining face134 need not be movable at all, and remain in place when the retainingmember is moved to its removal position. In such embodiments, moving theretaining member 106 its removal position includes moving the chainretaining face 136, but not the chain retaining face 134.

Optionally, the retaining member 106 may be locked in either itsretaining position, its removal position, or both, using any suitablelocking member or mechanism, and optionally may include two or morelocking mechanism. In some configurations, the locking mechanism forsecuring the retaining member 106 may be the same as the fastener thatis used to secure the retaining member 106 to the height adjustmentmember 104, such as fastener 142. Alternatively, the locking mechanismfor the retaining member 106 may be separate from, and optionally spacedapart from, its fastener and/or from its pivot axis.

Referring to FIG. 6, in the illustrated embodiment the fastener 142 alsofunctions as a locking member that can be used to lock the retainingmember 106 in position. If the fastener 142 is sufficiently tightened,the friction between the retaining member 106 and the height adjustmentmember 104 may lock the retaining member 106 in place. Correspondingly,if the fastener 142 is loosened, rotation between the retaining member106 and the height adjustment member 104 is permitted.

In the illustrated example, the chain guide 100 includes an alternatelocking mechanism for the retaining member in the form of a projectionor detent 168 (shown using hidden lines in FIG. 8) on the side of theretaining member 106 that engages with a corresponding recess 170 on theopposing surface of the height adjustment member 104. When the detent168 is received within the recess 170 it may tend to inhibit rotation ofthe retaining member 106 under normal riding conditions. This may beused in place of the fastener 142 to lock the retaining member 106. Topivot the retaining member 106, a user may apply a sufficient torque tothe retaining member 106 to overcome the interference and dislodge thedetent 168 from the recess 170, thereby disengaging the lockingmechanism. Preferably, the level of torque required is selected so thata user may rotate the retaining member 106 and overcome this lockingmechanism by hand—without the need for tools.

Optionally, instead of a detent/recess mechanism, the locking mechanismmay include a fastener that is separate from the mounting fastener 142and that can inhibit rotation of the retaining member 106 when engaged.For example, such a locking fastener may extend through the retainingmember 106 an engage the height adjustment member 104 or other suitablestructure. The locking fastener may be a threaded fastener, or may be anon-threaded fastener such as a pin, clip, clamp and the like. Forexample, a non-threaded pin may be inserted through the retaining member106 and into a corresponding hole in the height adjustment member 104.When the pin is inserted, rotation is inhibited and when the pin isremoved, rotation is allowed. Similarly a threaded fastener may beinserted through the retaining member 106 and threaded into acomplimentary boss on the height adjustment member 104. When thethreaded fastener is in place rotation is inhibited, and when thethreaded fastener is removed, rotation is allowed. Optionally, thelocking fastener may be arranged to be generally parallel to themounting fastener. In some configurations, the heads of both fastenersmay remain exposed to a user when the chain guide is assembled, whichmay help facilitate access.

Optionally, the fastener 142 may be used as a locking member incombination with the detent/recess mechanism. In this configuration, thedetent 168 may be inserted into the recess 170 to provide a first levelof locking, and then the fastener 142 may be tightened to provide asecond level of locking. To disengage the locks, the fastener 142 mayfirst be loosened, and then the retaining member 106 pivoted todisengage the detent 168 from the recess 170. This may provide a back-uplocking feature in the event that the fastener 142 could becomeinadvertently loosened when the bicycle is in use.

If the fastener 142 is removed entirely, the retaining member 106 may bedetachable from the height adjustment member 104. As the fastener 142 isseparate from the mechanism associated with the height settings,detaching and re-attaching the retaining member 106 may be done withoutloosening the fastener 118 and without affecting the height settings ofthe chain guide. If the retaining member 106 is in its removal position(FIG. 10) such that all of the retaining member 106 is above theclearance plane 160, the retaining member 106 may be laterallytranslated away from the height adjustment member 104 for removal whilethe chain guide 100 is attached to the bicycle—and without first raisingthe height adjustment member 104.

This description is meant to be illustrative and alternate mountingarrangements such as pins, rods or rivets instead of bolts or nutsinstead of threaded holes may be used to connect the chain guide to abicycle, or to attached the chain guide components to each other whilestill obtaining some or all of the advantages and features describedherein. For example, the mounting style shown for the base frame 102 inthe illustrated example is known as ISCG05 but various other standardmounting arrangements function in an analogous manner. Other framemounting standards that may be used with the teachings described herein,for example as the mounting portion of the base frame 102, include butare not limited to High Direct Mount, Low Direct Mount, E-type, S1, S2,S3, ISCG, ISCG03, BB mount, Side Direct Mount.

While the above description provides examples of one or more apparatus,methods, or systems, it will be appreciated that other apparatus,methods, or systems may be within the scope of the claims as interpretedby one of skill in the art.

The invention claimed is:
 1. A chain guide for a bicycle having achainring and a chain, the chain guide comprising: a) a base framehaving a mounting portion for connecting to a bicycle; b) a heightadjustment member connected to the base frame and slidable relative tothe base frame whereby the height adjustment member is movable relativeto the base frame and is lockable in a first position by engaging afirst locking member; c) a retaining member pivotally connected to theheight adjustment member and being pivotable about a pivot axis that isspaced apart from the first locking member while the height adjustmentmember is locked in the first position, and wherein the retaining memberis lockable in a retaining position by engaging a second locking memberthat extends through at least a portion of the retaining member, andwherein the second locking member is spaced apart from the first lockingmember and can be engaged and disengaged independent of whether thefirst locking member is engaged or disengaged; wherein when the baseframe is connected to the bicycle with the height adjustment memberlocked in the first position and the retaining member positionedproximate a periphery of the chainring the retaining member is pivotablebetween the retaining position, in which the retaining member ispositioned to obstruct lateral movement of the chain away from thechainring thereby preventing lateral misalignment between the chain andthe chainring, and a removal position, in which the retaining memberdoes not obstruct lateral movement of the chain away from the baseframe.
 2. The chain guide of claim 1, wherein the retaining member has afirst end and a second end that comprises the pivot axis and is spacedfrom the first end in a direction that is parallel a direction of travelof the chain relative to the retaining member.
 3. The chain guide ofclaim 2, wherein the first end is spaced apart from the heightadjustment member and the second end is adjacent and overlies the heightadjustment member.
 4. The chain guide of claim 3, wherein the retainingmember comprises a bottom face that is downward facing when the baseframe is connected to the bicycle and the retaining member is in theretaining position, and an end face at the second end, and wherein adistance between the pivot axis and the bottom face in a first directionis greater than a distance between the pivot axis and the end face in asecond direction that is orthogonal to the first direction.
 5. The chainguide of claim 1, wherein the retaining member is connected to theheight adjustment member by a mounting fastener that extends through theretaining member and is co-axial with the pivot axis whereby theretaining member pivots about the mounting fastener.
 6. The chain guideof claim 5, wherein the second locking member comprises the mountingfastener, whereby the second locking member is disengaged by looseningthe mounting fastener and engaged by tightening the mounting fastenerand the retaining member pivots about second locking member.
 7. Thechain guide of claim 1, wherein the second locking member comprises athreaded fastener and the second locking member is disengaged byloosening the threaded fastener and engaged by tightening the threadedfastener.
 8. The chain guide of claim 7, wherein the threaded fastenerextends through the retaining member and threadingly engages the heightadjustment member.
 9. The chain guide of claim 1, wherein the firstlocking member comprises a first threaded fastener and is disengaged byloosening the first threaded fastener and engaged by tightening thefirst threaded fastener, and the second locking member comprises asecond threaded fastener that is parallel to and offset from the firstthreaded fastener, and wherein the second locking member is disengagedby loosening the second threaded fastener and engaged by tightening thesecond threaded fastener.
 10. The chain guide of claim 1, wherein whenthe base frame is connected to the bicycle, the height adjustment memberis in the first position and the retaining member is positionedproximate the periphery of the chainring, the retaining member can belaterally translated away from the base frame in the direction of thepivot axis while in the removal position and is obstructed fromtranslating away from the base frame by the chainring when in theretaining position.
 11. The chain guide of claim 1, wherein when thebase frame is connected to the bicycle with the height adjustment memberlocked in the first position and the retaining member is positionedproximate a periphery of the chainring and in the removal position theretaining member is translatable laterally away from the heightadjustment member while the height adjustment member is locked in thefirst position to detach the retaining member from the height adjustmentmember.
 12. The chain guide of claim 1, wherein the retaining membercomprises a first chain retaining face and an opposing second chainretaining face that is laterally spaced apart from and faces the firstchain retaining surface, whereby when the base frame is connected to thebicycle the chain is disposed laterally between the first and secondchain retaining faces, and wherein the retaining member pivots in afirst direction about the pivot axis from the retaining position to theremoval position substantially the entire first and second chainretaining surfaces move in the first direction away from the chain. 13.The chain guide of claim 1, wherein retaining member comprises a firstchain retaining face and an opposing second chain retaining face that islaterally spaced apart from and faces the first retaining surface,whereby when the base frame is connected to the bicycle and theretaining member is in the retaining position the chain is disposedlaterally between the first and second chain retaining faces and aclearance plane defining an upper surface of the chain intersects thefirst and second chain retaining faces, and when the retaining member isin the removal position it is disposed entirely above the clearanceplane.
 14. The chain guide of claim 1, wherein the height adjustmentmember includes a sliding surface and the base frame includes acomplimentary abutment surface such that engagement between the slidingsurface and abutment surface prevents rotation of the height adjustmentmember relative to the base frame while permitting only lineartranslation therebetween.
 15. The chain guide of claim 14, wherein thebase frame is securable to the bicycle using at least one base fastenerthat is spaced apart from the first locking member, and wherein thefirst locking member can be engaged and disengaged independent of the atleast one base fastener.
 16. The chain guide of claim 1, wherein whenthe base frame is connected to the bicycle the retaining member formsthe upper most part of the chain guide when the height adjustment memberis in the first position and when the height adjustment member is movedto a different, second position relative to the base frame.
 17. A chainguide for a bicycle having a chainring and a chain, the chain guidecomprising: a) a base frame having a mounting portion for connecting toa bicycle; b) a height adjustment member connected to the base frame andslidable relative to the base frame whereby the height adjustment memberis movable relative to the base frame and is lockable in a firstposition by engaging a first locking member; c) a retaining memberpivotally connected to the height adjustment member and spaced apartfrom the first locking member, the retaining member being pivotableabout a pivot axis while the height adjustment member is locked in thefirst position and comprises a first chain retaining face and anopposing second chain retaining face that is laterally spaced apart fromand faces the first retaining surface a first chain retaining face;wherein when the base frame is connected to the bicycle with the heightadjustment member locked in the first position and the retaining memberpositioned proximate a periphery of the chainring the retaining memberis pivotable between a retaining position, in which the chain isdisposed laterally between the first and second chain retaining faceswhereby engagement between the chain and the first and second chainretaining faces obstructs lateral movement of the chain away from thechainring, and a removal position, in which the first and second chainretaining faces are spaced above the chain and the retaining member doesnot obstruct lateral movement of the chain away from the base frame, andwherein the retaining member is lockable in the retaining position byengaging a second locking member that extends through at least a portionof the retaining member, and wherein the second locking member is spacedapart from the first locking member and can be engaged and disengagedindependent of whether the first locking member is engaged ordisengaged.
 18. The chain guide of claim 17, wherein the wherein theretaining member is connected to the height adjustment member by amounting fastener that extends through the retaining member and engagesthe height adjustment member and is co-axial with the pivot axis wherebythe retaining member pivots about the mounting fastener, and wherein themounting fastener is spaced apart from the first and second chainretaining faces.
 19. The chain guide of claim 17, wherein the firstlocking member comprises a first threaded fastener which extends througha slot in the base frame and is disengaged by loosening the firstthreaded fastener and engaged by tightening the first threaded fastener,and the second locking member comprises a second threaded fastener thatis parallel to and offset from the first threaded fastener, and whereinthe second locking member is disengaged by loosening the second threadedfastener and engaged by tightening the second threaded fastener.
 20. Thechain guide of claim 17, wherein when the retaining member is in theretaining position a clearance plane defined by an upper surface of thechain intersects the first and second chain retaining faces, and whereinthe retaining member is pivotable without disengaging the first lockingmember into the removal position in which the entirety of the retainingmember is disposed entirely above the clearance plane.